User blog comment:Yoshi574930Cool/HAPPY BIRTHDAY MEWTWO!/@comment-31267872-20180206022005

So, I used Ctrl + F and found that... uh...
 * One of the Pokémon Mansion journals states that Mewtwo's birthday is February 6.
 * The same journal implies that Mew was impregnated with the modified clone, as in real life cloning. All other depictions show Mewtwo being grown using laboratory equipment.